As is well known in the art, rubber linings are installed in tanks and other vessels to protect the vessel body (typically, steel) from corrosive or abrasive products carried in the vessel. The rubber lining is first secured to the tank wall using an adhesive system, and then vulcanized with steam, so that the rubber lining is bonded to the vessel body or wall. Conventionally, the wall is made of any suitable material, e.g., steel.
Although the useful life of a rubber lining is usually relatively long (e.g., three to 25 years), rubber linings are sometimes damaged in use, and must be repaired. For example, if a relatively small portion of the rubber lining is damaged, it must be replaced.
In the prior art, this may be done by, first, removing the damaged portion from the lining and positioning a patch of new rubber material in the hole resulting from removal of the damaged portion. The new rubber material can be secured to the vessel wall by an adhesive system, but it also has to be vulcanized, or cured. Currently the curing of the rubber lining repair patch can be achieved either chemically, or by steam.
Each of these methods has disadvantages. For instance, when the rubber patch is cured chemically, only the exposed surface of the patch is cured immediately, and the balance of the patch cures gradually over time. Curing the rubber patch with steam is difficult and time-consuming, as the entire vessel may be filled with the steam for a predetermined time period or it is necessary to isolate the rubber patch to ensure that the steam does not damage the surrounding lining.
There are other circumstances where vulcanization is difficult to achieve due to the nature of the part or area to be vulcanized or its position. For instance, certain elements of a tank or a railcar (e.g., flanges, or manways) are difficult to vulcanize with steam.